CVE-2026-8927 - Vulnerability Details

- env-set cross-proxy Digest auth state leak

Description

When reusing a libcurl handle for sequential transfers driven by
environment-variable proxy configuration, libcurl fails to clear the proxy
authentication state between requests. Specifically, if the initial transfer
authenticates against `proxyA` using Digest auth, a subsequent transfer routed
through `proxyB` erroneously leaks the `Proxy-Authorization:` header intended
solely for `proxyA`.

Published: 2026-07-03

Score: 9.1 Critical

EPSS: < 1% Very Low

KEV: No

Impact:

Action:

Analysis

Analysis and contextual insights are available on OpenCVE Cloud.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions

curl

unaffected

Version	Status	Constraints
`8.20.0`	affected	≤ 8.20.0
`8.19.0`	affected	≤ 8.19.0
`8.18.0`	affected	≤ 8.18.0
`8.17.0`	affected	≤ 8.17.0
`8.16.0`	affected	≤ 8.16.0
`8.15.0`	affected	≤ 8.15.0
`8.14.1`	affected	≤ 8.14.1
`8.14.0`	affected	≤ 8.14.0
`8.13.0`	affected	≤ 8.13.0
`8.12.1`	affected	≤ 8.12.1
`8.12.0`	affected	≤ 8.12.0
`8.11.1`	affected	≤ 8.11.1
`8.11.0`	affected	≤ 8.11.0
`8.10.1`	affected	≤ 8.10.1
`8.10.0`	affected	≤ 8.10.0
`8.9.1`	affected	≤ 8.9.1
`8.9.0`	affected	≤ 8.9.0
`8.8.0`	affected	≤ 8.8.0
`8.7.1`	affected	≤ 8.7.1
`8.7.0`	affected	≤ 8.7.0
`8.6.0`	affected	≤ 8.6.0
`8.5.0`	affected	≤ 8.5.0
`8.4.0`	affected	≤ 8.4.0
`8.3.0`	affected	≤ 8.3.0
`8.2.1`	affected	≤ 8.2.1
`8.2.0`	affected	≤ 8.2.0
`8.1.2`	affected	≤ 8.1.2
`8.1.1`	affected	≤ 8.1.1
`8.1.0`	affected	≤ 8.1.0
`8.0.1`	affected	≤ 8.0.1
`8.0.0`	affected	≤ 8.0.0
`7.88.1`	affected	≤ 7.88.1
`7.88.0`	affected	≤ 7.88.0
`7.87.0`	affected	≤ 7.87.0
`7.86.0`	affected	≤ 7.86.0
`7.85.0`	affected	≤ 7.85.0
`7.84.0`	affected	≤ 7.84.0
`7.83.1`	affected	≤ 7.83.1
`7.83.0`	affected	≤ 7.83.0
`7.82.0`	affected	≤ 7.82.0
`7.81.0`	affected	≤ 7.81.0
`7.80.0`	affected	≤ 7.80.0
`7.79.1`	affected	≤ 7.79.1
`7.79.0`	affected	≤ 7.79.0
`7.78.0`	affected	≤ 7.78.0
`7.77.0`	affected	≤ 7.77.0
`7.76.1`	affected	≤ 7.76.1
`7.76.0`	affected	≤ 7.76.0
`7.75.0`	affected	≤ 7.75.0
`7.74.0`	affected	≤ 7.74.0
`7.73.0`	affected	≤ 7.73.0
`7.72.0`	affected	≤ 7.72.0
`7.71.1`	affected	≤ 7.71.1
`7.71.0`	affected	≤ 7.71.0
`7.70.0`	affected	≤ 7.70.0
`7.69.1`	affected	≤ 7.69.1
`7.69.0`	affected	≤ 7.69.0
`7.68.0`	affected	≤ 7.68.0
`7.67.0`	affected	≤ 7.67.0
`7.66.0`	affected	≤ 7.66.0
`7.65.3`	affected	≤ 7.65.3
`7.65.2`	affected	≤ 7.65.2
`7.65.1`	affected	≤ 7.65.1
`7.65.0`	affected	≤ 7.65.0
`7.64.1`	affected	≤ 7.64.1
`7.64.0`	affected	≤ 7.64.0
`7.63.0`	affected	≤ 7.63.0
`7.62.0`	affected	≤ 7.62.0
`7.61.1`	affected	≤ 7.61.1
`7.61.0`	affected	≤ 7.61.0
`7.60.0`	affected	≤ 7.60.0
`7.59.0`	affected	≤ 7.59.0
`7.58.0`	affected	≤ 7.58.0
`7.57.0`	affected	≤ 7.57.0
`7.56.1`	affected	≤ 7.56.1
`7.56.0`	affected	≤ 7.56.0
`7.55.1`	affected	≤ 7.55.1
`7.55.0`	affected	≤ 7.55.0
`7.54.1`	affected	≤ 7.54.1
`7.54.0`	affected	≤ 7.54.0
`7.53.1`	affected	≤ 7.53.1
`7.53.0`	affected	≤ 7.53.0
`7.52.1`	affected	≤ 7.52.1
`7.52.0`	affected	≤ 7.52.0
`7.51.0`	affected	≤ 7.51.0
`7.50.3`	affected	≤ 7.50.3
`7.50.2`	affected	≤ 7.50.2
`7.50.1`	affected	≤ 7.50.1
`7.50.0`	affected	≤ 7.50.0
`7.49.1`	affected	≤ 7.49.1
`7.49.0`	affected	≤ 7.49.0
`7.48.0`	affected	≤ 7.48.0
`7.47.1`	affected	≤ 7.47.1
`7.47.0`	affected	≤ 7.47.0
`7.46.0`	affected	≤ 7.46.0
`7.45.0`	affected	≤ 7.45.0
`7.44.0`	affected	≤ 7.44.0
`7.43.0`	affected	≤ 7.43.0
`7.42.1`	affected	≤ 7.42.1
`7.42.0`	affected	≤ 7.42.0
`7.41.0`	affected	≤ 7.41.0
`7.40.0`	affected	≤ 7.40.0
`7.39.0`	affected	≤ 7.39.0
`7.38.0`	affected	≤ 7.38.0
`7.37.1`	affected	≤ 7.37.1
`7.37.0`	affected	≤ 7.37.0
`7.36.0`	affected	≤ 7.36.0
`7.35.0`	affected	≤ 7.35.0
`7.34.0`	affected	≤ 7.34.0
`7.33.0`	affected	≤ 7.33.0
`7.32.0`	affected	≤ 7.32.0
`7.31.0`	affected	≤ 7.31.0
`7.30.0`	affected	≤ 7.30.0
`7.29.0`	affected	≤ 7.29.0
`7.28.1`	affected	≤ 7.28.1
`7.28.0`	affected	≤ 7.28.0
`7.27.0`	affected	≤ 7.27.0
`7.26.0`	affected	≤ 7.26.0
`7.25.0`	affected	≤ 7.25.0
`7.24.0`	affected	≤ 7.24.0
`7.23.1`	affected	≤ 7.23.1
`7.23.0`	affected	≤ 7.23.0
`7.22.0`	affected	≤ 7.22.0
`7.21.7`	affected	≤ 7.21.7
`7.21.6`	affected	≤ 7.21.6
`7.21.5`	affected	≤ 7.21.5
`7.21.4`	affected	≤ 7.21.4
`7.21.3`	affected	≤ 7.21.3
`7.21.2`	affected	≤ 7.21.2
`7.21.1`	affected	≤ 7.21.1
`7.21.0`	affected	≤ 7.21.0
`7.20.1`	affected	≤ 7.20.1
`7.20.0`	affected	≤ 7.20.0
`7.19.7`	affected	≤ 7.19.7
`7.19.6`	affected	≤ 7.19.6
`7.19.5`	affected	≤ 7.19.5
`7.19.4`	affected	≤ 7.19.4
`7.19.3`	affected	≤ 7.19.3
`7.19.2`	affected	≤ 7.19.2
`7.19.1`	affected	≤ 7.19.1
`7.19.0`	affected	≤ 7.19.0
`7.18.2`	affected	≤ 7.18.2
`7.18.1`	affected	≤ 7.18.1
`7.18.0`	affected	≤ 7.18.0
`7.17.1`	affected	≤ 7.17.1
`7.17.0`	affected	≤ 7.17.0
`7.16.4`	affected	≤ 7.16.4
`7.16.3`	affected	≤ 7.16.3
`7.16.2`	affected	≤ 7.16.2
`7.16.1`	affected	≤ 7.16.1
`7.16.0`	affected	≤ 7.16.0
`7.15.5`	affected	≤ 7.15.5
`7.15.4`	affected	≤ 7.15.4
`7.15.3`	affected	≤ 7.15.3
`7.15.2`	affected	≤ 7.15.2
`7.15.1`	affected	≤ 7.15.1
`7.15.0`	affected	≤ 7.15.0
`7.14.1`	affected	≤ 7.14.1
`7.14.0`	affected	≤ 7.14.0
`7.13.2`	affected	≤ 7.13.2
`7.13.1`	affected	≤ 7.13.1
`7.13.0`	affected	≤ 7.13.0
`7.12.3`	affected	≤ 7.12.3
`7.12.2`	affected	≤ 7.12.2
`7.12.1`	affected	≤ 7.12.1
`7.12.0`	affected	≤ 7.12.0

No data.

Vendor Product Confidence Versions

Curl

100%

Version	Status	Scheme	Platform
`[7.12.0,8.20.0]`	affected	semver	—

Found an issue or want to improve our Enrichment? You can suggest it directly by opening an issue on our dedicated GitHub repository .

Remediation

No vendor fix or workaround currently provided.

Additional remediation guidance may be available on OpenCVE Cloud.

Tracking

Sign in to view the affected projects.

Advisories

Source	ID	Title
Ubuntu USN	USN-8487-1	curl vulnerabilities

No CVSS v4.0

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact High

Integrity Impact High

Availability Impact None

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

The EPSS score is 0.0025.

Exploitation poc

Automatable no

Technical Impact total

References

Link	Providers
https://curl.se/docs/CVE-2026-8927.html
https://curl.se/docs/CVE-2026-8927.json
https://hackerone.com/reports/3744543
https://nvd.nist.gov/vuln/detail/CVE-2026-8927
https://www.cve.org/CVERecord?id=CVE-2026-8927

History

Tue, 07 Jul 2026 00:15:00 +0000

Type	Values Removed	Values Added
Weaknesses		CWE-201
References		https://nvd.nist.gov/vuln/detail/CVE-2026-8927 https://www.cve.org/CVERecord?id=CVE-2026-8927
Metrics	threat_severity `None`	threat_severity `Important`

Mon, 06 Jul 2026 22:45:00 +0000

Type	Values Removed	Values Added
Weaknesses	CWE-200

Mon, 06 Jul 2026 17:30:00 +0000

Type	Values Removed	Values Added
Metrics		cvssV3_1 `{'score': 9.1, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N'}` ssvc `{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'total'}, 'version': '2.0.3'}`

Sun, 05 Jul 2026 12:30:00 +0000

Type	Values Removed	Values Added
Weaknesses		CWE-200

Sun, 05 Jul 2026 01:15:00 +0000

Type	Values Removed	Values Added
Weaknesses	CWE-200 CWE-306

Sat, 04 Jul 2026 09:45:00 +0000

Type	Values Removed	Values Added
Weaknesses		CWE-200 CWE-306

Fri, 03 Jul 2026 21:00:00 +0000

Type	Values Removed	Values Added
Weaknesses	CWE-200

Fri, 03 Jul 2026 11:00:00 +0000

Type	Values Removed	Values Added
First Time appeared		Curl Curl curl
Vendors & Products		Curl Curl curl

Fri, 03 Jul 2026 10:00:00 +0000

Type	Values Removed	Values Added
Weaknesses		CWE-200

Fri, 03 Jul 2026 06:45:00 +0000

Type	Values Removed	Values Added
Description		When reusing a libcurl handle for sequential transfers driven by environment-variable proxy configuration, libcurl fails to clear the proxy authentication state between requests. Specifically, if the initial transfer authenticates against `proxyA` using Digest auth, a subsequent transfer routed through `proxyB` erroneously leaks the `Proxy-Authorization:` header intended solely for `proxyA`.
Title		env-set cross-proxy Digest auth state leak
References		https://curl.se/docs/CVE-2026-8927.html https://curl.se/docs/CVE-2026-8927.json https://hackerone.com/reports/3744543

Subscriptions

Curl Curl

MITRE

Status: PUBLISHED

Assigner: curl

Published: 2026-07-03T06:16:06.376Z

Updated: 2026-07-06T17:01:06.213Z

Reserved: 2026-05-19T08:12:08.842Z

Link: CVE-2026-8927

Vulnrichment

Updated: 2026-07-06T17:01:00.942Z

NVD

No data.

Redhat

Severity : Important

Publid Date: 2026-07-03T06:16:06Z

Links: CVE-2026-8927 - Bugzilla

OpenCVE Enrichment

Updated: 2026-07-07T12:15:06Z

Weaknesses

CWE-201

Tracking

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact High

Integrity Impact High

Availability Impact None

User Interaction None

Exploitation poc

Automatable no

Technical Impact total

Subscriptions

JSON object

JSON object

JSON object

JSON object

JSON object